The OLED (Organic Light Emitting Diode) devices have advantages of self-illumination, wide viewing angle, high speed response, high contrast ratio, ultra-thinness, and flexible folding. However, there is only 20% of the total light generated by OLED structures can illuminate out of the OELD device. How to improve the optical coupling output efficiency of OLEDs through simple processes is essential for the industrialization of OLED technology. For this reason, people use the periodical distribution array on the light-emitting surface of the OLED device, and utilize the scattering and refraction characteristics with the periodic distribution array to improve the optical coupling efficiency of the OLED device.
There are generally two methods for preparing a periodic distribution array on the light-emitting surface of the OLED device. One is the use of chemical methods, combined with photoresist, and then exposure and development to form the above-mentioned periodic array. But, this method requires the repeated use of a chemical solution, which tends to corrode other structures of the OLED device. The other method is to prepare the above-mentioned periodical distribution array by filming with a metal mask, but this method is very costly, and the metal mask is difficult to clean after use, and becomes thicker afterwards, resulting in uneven film formation and poor optical coupling efficiency of the OLED device.